mavros wng: RTT too high for timesync

[AnthonyZJiang]

This can be fixed by increasing simulation rate in Unity but isn't practical because it lags the system significantly.

[AnthonyZJiang]

RTT stands for round trip time. The code related to this warning can be found here. It is printed when rtt_ns < max_rtt_sample * 1000000ULL.

max_rtt_sample can be adjusted in ros param as the value is assigned by:

nh.param("time/max_rtt_sample", max_rtt_sample, 10);				// in ms

(see original code)

It is default to 10 ms, so you would need to reduce value of the simulation rate to 0.01 at least. Otherwise, set time/max_rtt_sample to match the simulation rate.

[AnthonyZJiang]

Found this in Ardupilot documentation:

If the RTT too high for timesync message is shown in the Mavros console (most commonly when using ArduRover), the SCHED_LOOP_RATE parameter should be increased. This is because Mavros ignores TIMESYNC messages if the round trip time is more than 10ms.